Indiana Department of Natural Resources sent this bulletin at 07/11/2017 02:41 PM EDT
Weekly Review for July 11, 2017
Indiana Department of Natural Resources Division of Entomology & Plant Pathology Phone: (317) 232-4120 Our Website Inspector Territories
This informal report by the Division of Entomology and Plant Pathology is designed to update the Nursery and Greenhouse industry of insect and disease pests the Division has been encountering on a week to week basis and as a way to give a “heads up” of things to be on the lookout for.
Links can be found at the bottom of the page to manage your subscription to this list. Comments and questions about this report are welcome and can be sent to Eric Biddinger or to your respective
Inspector.
Finished Carroll County this week. Finds this week included maple mite on the Red Maples, cedar apple rust on crabapples, quince rust on hawthorns, hawthorn leaf miner damage, potato leaf hopper injury on maples, and a whole lot of Japanese beetle damage, especially on elms.
Every once in a while you just find something cool. The Polyphemus moth caterpillar is large – up to 4 inches long. While they do eat a considerable amount of foliage, they have several natural enemies that reduce their numbers, thus limiting their economic impact.
I inspected nurseries in Allen, Dekalb and Grant Counties this past week. I found my first bagworms of the year on river birch in Allen County. There were only a few and they weren’t causing very much damage. Aphid populations are still high on some plants. They were heaviest on crabapples with lighter populations on river birch. Red headed flea beetle was the most abundant pest that I encountered this past week and they were feeding on a variety of different plants. I found them on Weigela, Hydrangea, Itea, Turtlehead, Coral Bells, Bergenia, Hyssop and Joe Pye weed. I found moderate populations of maple mite causing damage to ‘Autumn Blaze’ and red maple. Maple bladder gall was also very heavy on ‘Autumn Blaze” maple at one nursery. Potato leaf hopper populations were moderate on maples, but I found heavier damage on pin oak at one nursery. As for diseases I found powdery mildew on Sycamore, magnolia, dogwood and swamp white oak. Cedar Quince and cedar hawthorn rust were present on both thornless and ‘Winter King’ hawthorn. I also found Septoria leaf spot on red and yellow twig dogwoods, and apple scab was moderate to heavy on crabapples depending on the variety.
I attended a beekeeper meeting on Saturday. We had good weather to go in the hives. We went through some of the beekeeper’s nucs (nucleus hive made up of only 5 frames) that he was raising new queens in. Several of these nucs were collapsing. They had a queen but not enough bees to feed the larvae. The bees were not cleaning up the dead brood either. A healthy hive will clean out dead larvae or pupae. He was planning on destroying the bees and frames. The nucs are too weak to save. If you catch it early enough you could put some brood from another hive in there. I like to tell beekeepers to put capped brood in instead of open brood. Capped brood does not need to be feed and when they hatch out they will increase the numbers of nurse bees in the hive. Small hive beetle larvae were starting to show up with the nucs as well.
Nurse bees are important since they are feeding the larvae. The more nurse bees there are the more larvae they can feed. One larvae can be visited about 1,300 times in one day. Beeculture.com has a good article on nurse bees.
At inspections last week, two of the beekeeper’s hives had sacbrood starting. One was queenless and the other queen was not laying well. There were still enough bees in both hives to combine them. I recommended he collapse them down into a 2 story nuc box, purchase a queen, and get rid of most of the frames with dead brood in them. I also suggested feeding the bees some honey and pollen and trying probiotics for bees. He wanted the hive to make their own queen, but you do not want that stock. They were weak and would make a poor queen. You want to bring in a new mated queen right away. Also they need a queen now, as there were no good eggs or brood left.
At another hive inspection, the beekeeper had two hives with a small hive beetle problem. He had put in a new queen in one of them. The other was queenless. Both had a good amount of adult bee’s still. We ended up pulling frames of honey and pollen from both hives. This was due to small hive beetle larvae being on these frames. You have to get these frames out to save the bees. We used newspaper to combine the two hives. The beekeeper can extract some of the honey that was not slimed and he can mix it with some water and feed it back to the hives. The extracted frames can be frozen for 2 days to kill the small hive beetle adult, larvae and eggs. Once frozen he can reuse the frames that are in good condition.
Thursday through Saturday I will be at the Heartland Apicultural Society Annual meeting that is being held in Evansville this year. Let’s hope for good weather since I will be going into hives with beekeepers.
Over the past week, I’ve noted the following during inspections: powdery mildew on hydrangeas, virus symptoms on hosta, plant bug damage to ‘Sugar Shack’ Buttonbush, whiteflies on ‘Tiny Tortuga’ Chelone, mealybugs on ‘Russian Princess’ Lobelia, lace bug damage to rhododendrons and azaleas, Japanese Beetle damage to ‘Greenspire’ Linden and Cedar Hawthorn Rust on ‘Winterking’ Hawthorn. I get questions every year regarding control of rust on hawthorns and crabapples. Prevention is the key on this problem. These diseases need to be approached with a preventative treatment prior to spring bloom, then followed up with treatments at intervals based on your product label. Always follow product label instructions. These follow up treatments are needed especially if weather conditions are regularly wet.
I also wanted to share a photo that was sent to me of a Red Oak leaf and a situation where a homeowner was having a problem with their Red Oak tree dropping green leaves. These were green individual leaves dropping, not bunches of green and/or browned leaves with woody twigs being dropped. If anyone has had similar reports, please email me at - arust@dnr.IN.gov. If you have seen this, were you able to find any hollowed out areas or larvae at the base of the stems of the dropped leaves? Were there any extreme changes in soil wetness in the area of tree?
